A three-year-old girl heard screaming may have seen part of a knife attack that killed her mother at a home in the Christchurch suburb of Burwood in July.

The girl, now 4, was in her room when Paul Andrew Gottermeyer's attack began in the kitchen, just before her mother was to take her to preschool on July 11.

At Gottermeyer's sentencing in the High Court at Christchurch this morning, family members wondered what the long-term effect would be on the girl. She told police her mother screamed "and mummy did bleed everywhere".

Gottermeyer, a 29-year-old market gardener from Kaiapoi, argued with the woman before he produced the knife he had taken to her house. He said he shut the door to the kitchen where the attack took place, but left the child in the house when he left.

When the woman's partner arrived home because she had not arrived at work, he found the girl crying and upset in the conservatory and then found the woman and called the police.

Family members wept as Crown prosecutor Anselm Williams related details of the knife attack that killed the 24-year-old woman. He told of Gottermeyer inflicting wounds to the woman's head, chest, back and hands before cutting her throat.

The defensive wounds to her hands indicated she had been conscious during the early part of the ongoing attack.

There was also a blunt trauma wound to her skull but it was not possible to say whether this was inflicted by a blow with an object, or in a fall.

It was a "horrible attack of the utmost gravity", Justice John Fogarty said as he sentenced Gottermeyer to life imprisonment and gave him a first-strike warning which imposes heavier penalties on repeat violent offenders.

Another hearing has been set for February 28, to decide on the minimum non-parole term to be imposed on Gottermeyer. That decision is usually made at the sentencing, but it was not possible today because the necessary psychiatric report on Gottermeyer has only just been ordered.

An original psychiatric report examined his fitness to plead, but the new report is to cover his status as a mental health outpatient at the time of the murder and the medication he was taking.

Defence counsel Tony Greig argued for suppression of Gottermeyer's name, but it was refused by Justice Fogarty.

He said: "The court would be extremely loath to suppress the name of someone who has pleaded guilty to murder."

He suppressed the names of the murder victim and her daughter. Gottermeyer's name has been suppressed until today.

The victim's father said every aspect of his family's life had been changed by the murder of his daughter. He felt overwhelmed at times, with nightmares and broken sleep, and his relationship with his wife was strained.

A statement from the victim's stepfather said the girl who was at the house now suffered night tremors and nightmares.

Other family members also read statements, or had provided them to the judge in writing.

The victim's brother said the ongoing impact of the loss of his sister was indescribable.

"No tears, therapy, or sleepless nights will bring her back," he said.